Unidirectional hand tool



May 14, 1957 2,792,094

s, P. BALDW1N ET AL UNIDIRECTIONAL HAND Toor.

Filed Jan. 16, 1956 n A msn/5515141!!! l United States Patent UNIDIRECTIONAL HAND TOOL Stephen P. Baldwin, Concord, and George A. Wood, Jr.,

Lincoln, Mass., assignors to Arthur D. Little, Inc., Cambridge, Mass., a corporation of Massachusetts Application January 16, 1956, Serial No. 559,168

2 Claims. (Cl. 192-43) This invention relates to a reversible unidirectional hand tool, such as a screw driver, of the type employing a helical spring which grips the handle and working member when twisted in one direction, and which releases when twisted in the other direction.

In accordance with this invention there is provided a handle with a cylindrical hollow passage therethrough, in which passage are mounted two sleeves attached to and spaced apart by a shoulder member which also is joined rmly to the passage wall at approximately its center. These sleeves are spaced from said wall to accommodate helical springs, one on each sleeve and each of a different hand. Within the sleeves and shoulder member is a cylindrical passage extending the length thereof and adapted to receive the shank of the screw driver or other tool. The springs, shank, and sleeves are so arranged that each spring is normally in sliding tit engagement with lone sleeve over about half of its length, while the other half of its length is adapted to engage in sliding t with the tool shank when the shank is placed in that end of the handle. Thus, when the shank is placed in one end of the handle, turning of a screw or other object is accomplished in one direction, and when the shank is placed in the other end, turning is accomplished in the other direction.

This invention will now be described in connection with the accompanying drawings, wherein:

Fig. l is a View of the device of this invention as applied in the form of the unidirectional operative handle `of a screw driver, partly in longitudinal side elevation, and partly in diametrical cross-section;

Fig. 2 is a detail view of the helical spring;

Fig. 3 is a detail view of the cap members, within the handle of the screw driver, for receiving the helical spring member therein, and which may be separate from or integral with the handle;

Fig. 4 is a detail View of the sleeves and shoulder member, to be received within the helical spring member .and also attached to the handle at its center; and

Fig. 5 is a detail enlarged, cross-sectional view of the handle, sleeve, spring, and shank member, taken along S--S of Fig. l.

In the construction and assembly of the example of the device, as shown, the handle 1 may be made of any suitable material, such as wood, plastic, metal, or the like, and shaped to give a good hand grip for operation. vIt is provided with a central, longitudinal cylindrical yopening 2, receiving, with a snug tit, the cylindrical caps 3 and 4 therein, having shoulders 5, 6, at their outer ends, and spaced apart at the center, 7.

One sleeve portion of the sleeve and shoulder member 8, say 11, is adapted to receive upon it a helical spring 13, and the other sleeve portion 12, is adapted to receive upon it a like helical spring 14, which is coiled in the opposite sense, i. e., right hand and left hand, with respect to each other.

The helical spring, wound in closed turns of thin re- 2,792,094 Patented May 14, 1957 ICC silient, flat, strip material, is of an internal diameter such as to present a push tit, when relaxed, over the entire external cylindrical surface of its corresponding sleeve member, but not a loose it.

As thus assembled, the handle is ready to receive the operative member, such as the screw driver 15, having a head 16, a ferrule 17, adapted to it against one end of the handle, as shown in Fig. l, to position and seat the same in adjusted operative position, and a shank 1S which at its inner end 19 is of such diameter as to permit it to enter the cylindrical opening of either of the helical springs with a push lit in contact with them. Beyond section 19 the shank is turned down to a smaller diameter, as indicated at 21, thus providing a shoulder 20 which butts against sleeve 11 or 12, and thus permitting it to enter the cylindrical opening of the sleeve and shoulder member 8, as shown.

In assembly one of the caps may simply have the corresponding helical spring slipped into it and the corresponding sleeve slipped into the central, longitudinal, cylindrical opening of the said helical spring. The assembly thus arranged may be slid into the opening 2 of the handle, followed by the other cap and spring, or the other cap and spring may be slid over the sleeve at the other end and the complete assembly slipped into the opening 2 of the handle 1. In any event, the caps 3, 4 and the sleeve-and-shoulder member 8 are firmly fixed to the handle, as by friction iit or for example a pin 22 engaging the handle and the rib 9 on the member 8.

The complete hand tool is then ready for operation. Its operation will be described with respect to the position shown in Fig. l.

Upon now engaging the head of the screw driver with a screw and turning the same, in the direction of coiling up and hence attempting to -contract the helical spring i3,A the latter immediately binds tightly against both shank section 19 and sleeve 11 and thereby preventing any turning of the former with respect to the latter until the turning torque on the screw driver handle 1 is released. Immediately upon turning the handle in the opposite direction, the motion of sleeve 11 tends to uncoil spring 13 and thereby release it at once from its binding contact with shank section 19. A ratchet eliect is thus attained.

For oppositely unidirectional functioning of the hand tool, the tool member, whether screw driver or other like device, is inserted into the other end of the handle, where the helical screw 14 of `opposite hand, will function in the manner described above but of course in the opposite direction.

We claim:

l. A reversible unidirectional hand tool, comprising a handle member, a cylindrical opening extending longitudinally therethrough, first and second hollow helical spring members received and retained endwise in said cylindrical opening, free to rotate upon their axes therein, and to expand and contract radially in said opening, a cylindrical work member projecting beyond one end of said handle and extending within a portion of the rst hollow helical spring member and positioned longitudinally thereof, a first sleeve member likewise extending within a portion of said iirst hollow spring member and positioned longitudinally thereof, a second sleeve mem ber extending within a portion of said second hollow spring member and positioned longitudinally thereof, and a shoulder member rigidly attached to said handle and to said first and said second sleeve members, said second spring member being of opposite hand from said iirst spring member.

2. A reversible unidirectional hand tool comprising a tool member and a driving member therefor, said driving member comprising a rigid cylindrical member having a cylindrical passage longitudinally therethrough adapted to receive the shank of said tool member, said member consisting of two sleeves with a raised shoulder therebetween, a helical spring member tting over and in sliding-fit contact: with each of said sleeves, one spring member being of opposite hand from the other, each said spring member projecting beyond its corresponding sleeve and being adapted to grasp the shank of said tool member inserted within said cylindrical passage, and handle means surrounding said cylindrical member and said springs and rigidly attached to the former and spaced apart from the latter.

References Cited in the file of this patent UNITED STATES PATENTS 1,704,062 Starkey Mar. 5, 1929 

